Olefin resins such as polypropylene, polyethylene, ethylene-propylene copolymers, and ethylene-propylene-conjugated diene copolymers and low-polarity polymers such as styrene-butadiene copolymers and hydrogenated products thereof are extensively used for a variety of end uses such as electrical parts and automobile parts, in that they are inexpensive and have excellent properties such as chemical resistance and moldability.
However, when these low-polarity polyolefins are incorporated into coatings or inks so as to carry out coating or printing in order to protect a surface, to face, to record, etc., the resultant coatings or inks exhibit poor adhesion properties. In order to solve this problem, there are proposed use of a primer primarily containing modified polyolefins such as maleic anhydride-grafted hydrogenated styrene-butadiene block copolymers or maleic anhydride-grafted chlorinated polypropylene, and coatings containing a binder in which these modified polyolefins are incorporated. However, these grafted modified resins do not always provide satisfactory performance of resulting coating films in terms of low-temperature impact resistance or pigment dispersibility, and moreover, they do not always provide sufficient adhesion to polar resins. These drawbacks hamper application of the grafted modified resins to the field of adhesives, etc.
In view of the foregoing, there is strong demand for development of resin compositions for coating which exhibit stable and excellent adhesion to plastics, particularly to olefin resins, and which provide various advantages: affording coating films exhibiting excellent low-temperature impact resistance when used as a primer; permitting excellent pigment dispersion; exhibiting excellent adhesion to a variety of plastics; and being widely applicable to more extensive uses such as coatings, inks, and binders for adhesives. In the present invention, the word "for coating" connotes a broad concept and covers not only the above-described coatings but also inks and adhesives.